YM-09730 is a dihydropyridine-3,5-dicarboxylic acid ester derivative shown by the following chemical structure, the chemical name of which is 2,6-dimethyl-4-(3-nitropheny)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-(1-benzylpyrrolidin -3-yl)ester 5-methyl ester. ##STR1##
YM-09730 is the compound first synthesized by the researchers of the same company as the applicant of this application and it is reported that the compound has a vasodilating activity and a hypotensive activity, and also shows prolonged effect of about these activities (U.S. Pat. No. 4,220,649; U. K. Patent No. 2,014,134, etc.,).
YM-09730 has two asymmteric carbon atoms and it is assumed from the stereochemical view point that there are isomers based on these asymmeteric carbon atoms but there are no descriptions about these isomers in the above-described patents and the existence of these isomers was not confirmed.